A 62-year-old man presents to the clinic with dyspnea on exertion. He reports a progressive decline in his exercise tolerance over the last few years, and complains that he feels like he is always coughing up white mucus. He denies any fever, weight loss, hemoptysis, chest pain, or leg swelling. His medical history is significant for hyperlipidemia and GERD, for which he takes atorvastatin and omeprazole. He has smoked a pack of cigarettes daily for the past 40 years. He is afebrile with normal vitals. On examination, he has decreased breath sounds with a prolonged expiratory phase and scattered wheezes. There is hyper-resonance to percussion in bilateral lung fields. The rest of the examination is unremarkable, and he is referred for further testing with spirometry.
Which of the following represents the likely flow–volume loop in this patient (Figure below)?
Option B. COPD is a common condition resulting from chronic inflammation of the airways leading to progressive airflow limitation. Most cases occur in older patients and are the result of chronic smoking; in a young patient without a significant smoking history, consider other causes (such as α1-antitrypsin deficiency). There are two processes that typically occur in COPD: emphysema (a histopathologic finding) and chronic bronchitis (a clinical finding). The type of emphysema seen on histology is centrilobular, whereas in α1-antitrypsin deficiency it is panacinar. Emphysema is the result of parenchymal destruction from chronic inflammation, which creates enlarged airspaces. With the loss of the supporting connective tissue, the lungs lose their elastic recoil and the airspaces enlarge, creating high lung volumes; in addition, small airways collapse during expiration due to a loss of tethering that the connective tissue provides, which causes air trapping and further expansion in lung volumes. This affects respiratory function by decreasing both ventilation and perfusion via destruction of airspaces and vasculature, leading to mild hypoxemia.
Chronic bronchitis is defined as having a productive cough for more than 3 months of the year for at least 2 years. Inflammation of small airways causes narrowing and excessive sputum production leading to increased airway resistance and a prolonged expiratory phase. This causes V/Q mismatch and hypoxemia. The end result of both emphysema and chronic bronchitis is high lung volumes with increased compliance (large changes in volume based on small changes in pressure, the opposite of elasticity), leading to increased dead space during ventilation and chronic hypoxemia.
This patient presents with classic symptoms of dyspnea on exertion and chronic productive cough, with physical findings highly suggestive of COPD. Spirometry is required to make the diagnosis (decreased FEV1/FVC ratio), as not all patients will have the classic symptoms noted above. When flow– volume loops (spirograms) are constructed, there is a classic “scooped-out” appearance during expiration in obstructive lung diseases like COPD. This is caused by the pathologic changes in the airways in which the expiratory flow rapidly decreases due to loss of elastic recoil, increased airway resistance, and collapse of small airways. (A) This is a normal flow–volume loop. (C) With restrictive lung diseases, the flow–volume loop is smaller and shifted to the right. This is caused by an increase in elastic recoil of the lung leading to decreased lung volumes. (D) In patients with a fixed upper airway obstruction (e.g., subglottic stenosis), there is a limit to the airflow that can be generated during inspiration and expiration because of the fixed narrowing of the airway. This is seen as a plateau in the flow–volume loop.
A 42-year-old woman presents with progressive fatigue over the past few weeks. She reports muscle fatigue, occasional double vision, and some difficulty breathing. She has no relevant past medical history and takes no medications. On examination, sustained upward gaze leads to muscle fatigue and bilateral ptosis. Pulmonary function testing is performed and is shown below.
Which of the following is responsible for this patient’s pattern on pulmonary function testing?
Neuromuscular disease. Myasthenia gravis is a neuromuscular disease caused by autoantibodies directed against postsynaptic acetylcholine receptors. Neuromuscular diseases can show a restrictive pattern (decreased FEV1 and FVC but normal/increased FEV1/FVC ratio) on pulmonary function testing that is extrinsic to the lung itself and therefore will have a normal DLCO. Examples include lower motor neuron disease (e.g., polio and Guillain– Barré syndrome), myasthenia gravis, Lambert–Eaton syndrome, muscular dystrophies, chest wall deformities (e.g., scoliosis and pectus carinatum), and obesity. (A) COPD will present with an obstructive pattern on spirometry (decreased FEV1/FVC ratio) with a decreased DLCO (if there is a prominent component of emphysema). (C) Pulmonary fibrosis is a type of interstitial lung disease, which will show a restrictive pattern on spirometry as well as a decreased DLCO from parenchymal destruction and scarring. (D) Pulmonary hemorrhage would present with normal spirometry but an increased DLCO, since the presence of red blood cells within the airways will cause a rapid consumption of carbon monoxide during the test.
A 68-year-old woman with a history of hypothyroidism and COPD presents for follow-up with her primary care physician. She has no complaints and denies any recent fatigue, weight loss, increase in cough or sputum production, or chest pain. Her medications include inhaled ipratropium and levothyroxine. She is normotensive with an SaO2 of 92% on room air. On examination, her lungs are hyper-resonant to percussion with some scattered wheezes and rhonchi. She has clubbing of the digits, which was not present 1 year ago.
What is the most appropriate next course of action?
Chest imaging. Clubbing of the digits is not associated with COPD, and therefore any new onset of clubbing in a COPD patient is a red flag for another etiology such as bronchogenic carcinoma. Chest imaging is an important diagnostic step to look for cancer. Other etiologies of clubbing include interstitial lung disease, cystic fibrosis, congenital heart disease, and malabsorption. (A) Because the clubbing is unrelated to the patient’s COPD, reassurance is inappropriate. (B) This patient does not meet criteria for home oxygen therapy (SaO2 ≤ 88%). (C) The patient is not having an exacerbation and has no reason to undergo pulmonary function testing at this time.
A 46-year-old man with a history of ulcerative colitis is admitted to the hospital with abdominal pain and heavy rectal bleeding. Initial laboratory samples are drawn, and his hemoglobin is measured at 6 g/dL. He is given IV methylprednisolone and 2 units of packed red blood cells. Three hours later, the patient complains of shortness of breath and is given supplemental oxygen at an FiO2 of 30%. He appears anxious and is gasping for breath while speaking. There is no jugular venous distention or murmurs on cardiac examination. An arterial blood gas shows a PaO2 of 55 mmHg and a PaCO2 of 36 mmHg. A chest x-ray shows fluffy opacities in both lung fields with a normal cardiac silhouette
What intervention should be performed next?
Intubation and positive end-expiratory pressure (PEEP). A PaO2/FiO2 ratio ≤200 with pulmonary edema that is noncardiogenic – no jugular venous distention or elevated pulmonary capillary wedge pressure (PCWP) – meets criteria for acute respiratory distress syndrome (ARDS). The most common causes of ARDS are pneumonia, sepsis, and aspiration. The pathophysiology involves alveolar and capillary endothelial injury, which causes a strong inflammatory response and leakage of fluid into the lungs. This patient developed ARDS within 6 hours of a transfusion, making the most likely diagnosis transfusion-related acute lung injury (TRALI). Despite the name, TRALI can present with acute lung injury or ARDS. The management of ARDS involves intubation with mechanical ventilation targeting low tidal volumes and increased PEEP to help prop open alveoli for gas exchange.
(A) This patient suffered TRALI and therefore no more transfusions should be given at this time. However, patients that experience one episode of TRALI are not necessarily at an increased risk of TRALI in the future. (B) Hypervolemia can increase fluid leakage from damaged capillaries in the lung during ARDS. This patient is likely hypovolemic due to the heavy blood loss from ulcerative colitis, and therefore diuresis is not a good answer choice. (D) There is no role for plasmapheresis in ARDS or TRALI specifically.
A 52-year-old man presents to his physician with complaints of cough and difficulty breathing during exercise. He also endorses weight loss and night sweats that he noticed over the past few months. The patient has a history of diabetes and takes metformin. He works at a stone quarry, does not smoke or drink alcohol, and does not use any illicit drugs. A chest x-ray shows multiple small nodules in the upper lobes of each lung and multiple areas of calcification around lymph nodes.
Which of the following is the most appropriate next step in management?
Administer a tuberculin skin test. The diagnosis of silicosis is made by taking a history concerning for silica exposure, obtaining chest imaging that is consistent with silicosis, and ruling out other diseases that may mimic silicosis. Common environmental exposures to silica include stone quarries, mining, sand blasting, and construction. Chest imaging is somewhat variable based on the type of presentation (acute, chronic, or accelerated); however, it will typically show small nodules within the upper lobes. There may also be calcifications around lymph nodes (“eggshell calcifications”). Buzzwords like eggshell calcifications are good to know, but the test does not always give the buzzwords and may instead describe the findings!
Patients with silicosis may be asymptomatic or may present with cough and dyspnea on exertion. They are at an increased risk for tuberculosis, and therefore patients with a diagnosis of silicosis should undergo tuberculin skin testing with purified protein derivative (PPD). They are also at an increased risk of lung cancer, similar to other pneumoconiosis. (A) Elevated ACE may be seen in sarcoidosis, but this patient’s occupational history and chest x-ray suggest silicosis as the diagnosis. (B) Preventive therapy is the key in pneumoconiosis, and treatment after silicosis develops is typically based on symptom management. There are mixed results about the usefulness of glucocorticoids in the treatment of silicosis. (D) Additional workup is not necessary to make the diagnosis of silicosis.
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